Delhi: President Donald Trump has warned that the US will go to "Phase 2" if sanctions imposed on North Korea do not have the desired effects.

Trump made the statement during a joint news conference with Australian Prime Minister Malcolm Turnbull. "If the sanctions don't work, we will have to go to phase two, and phase two may be a very rough thing, may be very, very unfortunate for the world."

The president did not specify exactly what he meant by "Phase 2" and qualified the statement saying that he didn't think he was "going to exactly play that card."

Earlier the Trump administration announced its "largest ever" set of sanctions against Pyongyang. The restrictions were made against 50 vessels, shipping companies and trade businesses. North Korea uses its shipping industry to circumvent sanctions to fund its nuclear weapons and ballistic missile programs, according to the US Treasury.

Tensions between Pyongyang and Washington have remained tense while North Korea has made rapid progress in its nuclear program. Last week Secretary of State Rex Tillerson said the government won't deviate from its 'big stick' approach towards the nation. "This pressure campaign is having its bite on North Korea," Tillerson said.

Meanwhile an improvement in relations between North Korea and South Korea ahead of the Winter Olympics appears to have hit a stumbling block. South Korea's defense ministry confirmed earlier this week that joint military drills with the US would go ahead despite the recent detente.

South Korean lawmakers shifted from its strategy of dialogue Friday as more than 70 MPs gathered outside the presidential Blue House in Seoul calling for the public hanging of the leader of the North's Olympic delegation. North Korean General Kim Yong Chol, who is believed to have coordinated a series of attacks against the South, will lead a delegation that will attend the closing ceremony of the Pyeongchang Olympics Sunday.

The US and South Korea have repeatedly staged military drill close to North Korea, despite the crisis and warnings from Pyongyang. The latter has deemed the actions as provocative and stated at the end of last year the exercises combined with US threats are making the outbreak of war “an established fact."